Low-voltage heavy-current transformer



July 28, 1925. V I 1,547,497

- T. M. HUNTER Low VOLTAGE HEAVY CURRENT TRANSFORMER Filed Feb. 15. 1924 4' Fly] I? .L- i [r I J'IJJ I i 3 9 i i I 23 l6 l 20 i: -;1''Z/ I i I" zz fi: i r i V E M retested .Iul'y' 2a, 1925.. p

UNITED STATES PATENT o THOMAS M. HUNTER,

FFI'CE.

or NEWARK, New Jnasnr, .ASSIGNOR T0 AMERICAN' arms- FORMER. 00., or NEWARK, mzw JERSEY;

Low-venues rmAvY-ctmnmr rmsronmm Application filed February 15,19 4. Serial No. 692,957.

- To all whom it may concern:

Be it known that I, THOMAS M. HUNTER, a citizen of the United States, residing at Newark, in the county of Essex, State of New Jersey, have invented certain new and useful Improvements in a Low-Voltage Heavy-Current Transformer, of which the followin' is a description, reference being hadto, the accompanying drawing and to the figures of reference marked thereon.

This invention relates to the design of a low voltage heavy-T current transformer.

- Such transformers areused for'butt .welding and otherpurposes where a low voltage heavy alternating current is required.

. The principal object of my invention is to provide a transformerwhichshall be efiicient in its 0 ration and one that is simple and hence cheap to construct.

Myvinvention will be. best understood byreference tov the attached drawing, wherein:

. Figure l is a view of a, transformer of thepriorart; x 1 Figure 2 shows the construction of my improved form of secondary winding;

Figure 3 an end View of Fig. 2 'and Figure 4 is'a modified form of a detail hereinafter referred to.

In the variqus views,-1 illustratesthe core of a transformershown as bein made up of U-shaped laminations h'avinghmbs2 and I 3 which are closed by a yoke 4. On the .limb '2 is placed. one coil 5 ofthe ary winding constructed of U shaped memtaps were desired, it has been the practise P y windmg,'the other coil 6 being disposed on the limb 3. So far as applicant isaware, P

the transformers constructed for the pose above indicated, have .had the secondbers usually of 'cast copper, the limbs of which are insulated in any suitablemannen. These U shaped members are then slipped overone of the'primary coils and connections from one member to the. other completed by a cross-bar} screwed or "bolted to the ends of ,the'U shaped members. -.Where to rovide some sort of a stud. tapped at botl i ends so as to make connection with the end of, the U shaped member as well as to make connection at the outer end of the "This construction necessitates doing a certain amount of machine work on the faces of the studs as well as the U shaped.

members. Furthermore it introduces into the secondary circuit, as W111 seen, quite heated at 17 or they thereto. I

givm plenty the tap the transformer. After th has been all completed with its taps ular in cross section. This complete secondary is shown in Figs. 2 and 3, the winding starting with the terminal '14 and ending with the terminal 15. As shown in Fig.

2, each turn of the winding is provided with a tap. taps are preferably made from the same bar stock as the secondary 16 and are set endwise, preferably on the top part of the turns of the, secondary as indicated inuFig. 3, and are welded thereto as indimay be attached to the turns asshown in Fig. 4 wherein two pins 18 are used to project through the turns'16, being riveted prefer to, arrange these taps a1- terna'tely in diflerent planesso that for example taps 19 and 21 are in the same plane,

but are offset-from the end turns 14 and 15, which are in anothenplane, and the ta s 20 22 being in still another plane, thereby nals t ro h the medium of the holes 23 in g conductors or the end terminals. e taps, however, may be arranged diagonally across the top part of the secondary turns in the, direction indicated by the arrowinFigS. 1, a While I have shown turns whereb tained, it wil r o p to the turns ticular job which is td be taken care 0' taps on each of the be understood that the nilmand their location with" respect by e secondary and insulation ifiany is desired other than the insulationiwhich may be 'on the outer part of the coil, it is slipped over one of the rimarycoils in about the same position as mthe former typeof secondary winding as shown in Fig. 1, and the yoke 4 is then properly putinto position. By

continuous strip of good conducting material, preferably soft copper thatis rectang of room to attach the termi diflerent voltages may be obmay be varied to suit the ar v on theinside and sweated'. 4

usmg only one secondary coil associated with only a portion of the primary, I ob-.

tain a transformer having considerable reactance, so that when the turns of the secondary I are momentarily short-circuited as same cross section as the secondary welded they are'for some classes of work, such as butt welding, "no damage is done to the transformer. I r While I am aware that butt welding transformers have been used with a heavy conductor as a continuous winding, I be; lieve I am the first to associate taps, especially in the manner provided, for these heavy secondaryturns and I, therefore, do not .wish to be limited except as limited by the scope of the appended claims.

Having thus described my invention, whatIclaimis: I

1. In-a transformer of the class described,

' i5 adivid'ed primary winding on the core, a

continuous single layer secondary windingformed from tone-piece of good electrical conducting material having substantially a. .uniform cross section throughout its length and adapted to be passed over one portion ofthe primary, said secondary-having taps, of substantially the same cross sectional area as the secondary, welded thereto.

a dividedprimary winding on the core, a continuous'single layer secondary winding associated with one part oftheprimary, said secondary comprising a relatively few number-- of turns-rectangular in cross section and having taps of substantially the to each turn of the secondary in staggered relationship,' as and for the purpose dev scribed.

.2. In a transformer of the class described,

3. In a transformer of the class described,

a core, a primary winding on the c0re, a

continuous secondary on the core, a section through said secondary being rectangular in shape, said secondaryhavlng taps consisting of rectangular shaped bars set on end on the flat outer surface of any secondary turn desired and fastened-to said turn, 1

4. In a transformer of the class described, a core, a primary winding on .the core, a

continuous secondary on the core, a section through said secondary'being rectangular in shape, said secondary having taps consisting of rectangular. shaped bars set on end on the fiat outer surface of any secondary turn.desired, and securely fastened to said turn, said tapselgein'gset alternately in different planes.

'5. In a transformer of the class described, a c ore,-a primary winding onithe core, a continuous secondary on the core, a section through saidv secondary being rectangular in cross section, said secondary having taps consisting of rectangular shaped bars set on end on the flat outer surface of any secondary turn desired, and securely fastened to said turn, said taps being set on the turns intermediate the end turns so as to'lie in a 4 THOMAS M. HUNTER.

the 

